TrkB induces EMT and has a key role in invasion of head and neck squamous cell carcinoma

Head and neck squamous cell carcinoma (HNSCC) remains a significant public health problem, accounting for over 5% of all cancer-related deaths, and these deaths primarily result from metastatic disease. The molecular processes involved in HNSCC pathogenesis and progression are poorly understood, and here we present experimental evidence for a direct role of the cell surface receptor tyrosine kinase, TrkB, in HNSCC tumor progression. Using immunohistochemical analysis and transcriptional profiling of archival HNSCC tumor specimens, we found that TrkB and its secreted ligand, brain-derived neurotrophic factor (BDNF), are expresses in greater than 50% of human HNSCC tumors, but not in normal upper aerodigestive tract (UADT) epithelia. Studies with HNSCC cell lines reveal that in vitro stimulation with BDNF, the ligand for TrkB, upregulates the migration and invasion of HNSCC cells, and both transient and stable suppressions of TrkB result in significant abrogation of constitutive and ligand-mediated migration and invasion. Furthermore, enforced overexpression of TrkB results in altered expression of molecular mediators of epithelial-to-mesenchymal transition (EMT), including downregulation of E-cadherin and upregulation of Twist. Using an in vivo mouse model of HNSCC, we were able to show that downregulation of TrkB suppresses tumor growth. These results directly implicate TrkB in EMT and the invasive behavior of HNSCC, and correlate with the in vivo overexpression of TrkB in human HNSCC. Taken together, these data suggest that the TrkB receptor may be a critical component in the multi-step tumor progression of HNSCC, and may be an attractive target for much needed new therapies for this disease.

The role of GNAS and other imprinted genes in the development of obesity

Genomic imprinting is an epigenetic phenomenon affecting a small number of genes, which leads to differential expression from the two parental alleles. Imprinted genes are known to regulate fetal growth and a 'kinship' or 'parental conflict' model predicts that paternally and maternally expressed imprinted genes promote and inhibit fetal growth, respectively. In this review we examine the role of imprinted genes in postnatal growth and metabolism, with an emphasis on the GNAS/Gnas locus. GNAS is a complex imprinted locus with multiple oppositely imprinted gene products, including the G-protein alpha-subunit G(s)alpha that is expressed primarily from the maternal allele in some tissues and the G(s)alpha isoform XLalphas that is expressed only from the paternal allele. Maternal, but not paternal, G(s)alpha mutations lead to obesity in Albright hereditary osteodystrophy. Mouse studies show that this phenomenon is due to G(s)alpha imprinting in the central nervous system leading to a specific defect in the ability of central melanocortins to stimulate sympathetic nervous system activity and energy expenditure. In contrast mutation of paternally expressed XLalphas leads to opposite metabolic effects in mice. Although these findings conform to the 'kinship' model, the effects of other imprinted genes on body weight regulation do not conform to this model.

In vitro culture and differentiation of buffalo (Bubalus bubalis) spermatogonia

The objective of this study was to develop a culture system which could support buffalo spermatogonia differentiation into spermatids in vitro. Testes from 3- to 5-month-old buffaloes were decapsulated and seminiferous tubules were enzymatically dissociated to recover spermatogonia and sertoli cells. The cells were cultured in modified Dulbecco modified Eagle medium supplemented with different concentrations of foetal bovine serum, retinol, testosterone for 2 months at 37 degrees C. Spermatogonia and sertoli cells were identified with an antibody against c-kit or GATA4, respectively. The viability of spermatogonia in the media supplemented with different concentrations of serum was all significantly higher (p < 0.05) compared with that in the medium without serum. A-paired or A-aligned spermatogonia and spermatogonial colonies (AP-positive) were observed after 7-10 days of culture and spermatid-like cells with a flagellum (6-8 microm) appeared after 30 days of culture. For cultured conditions, retinol could not significantly promote the formation of spermatid-like cells (p > 0.05), whereas supplementation of testosterone could significantly promote (p < 0.05) the formation of spermatid-like cells after 41 days of culture. The expression of the spermatid-specific marker gene (PRM2) was identified after 30 days of culture by RT-PCR. Yet, the transition protein 1 (TP1, a haploid makers) was not detected. Meanwhile, spermatids developed in vitro were also confirmed by Raman spectroscopy. These results suggest that buffalo spermatogonia could differentiate into spermatids in vitro based on the analysis of their morphology, PRM2 expression and Raman spectroscopy. Yet, the normality of the spermatid-like cells was not supported by TP1 expression.

Interactions between stem cells and their niche in the Drosophila ovary

The Drosophila ovary contains at least three types of active stem cells, namely, germ-line stem cells (GSCs), escort stem cells (ESCs), and follicular stem cells (FSCs), which work together to efficiently assemble egg chambers. Among the three stem cell types, the GSC is among the first shown to be controlled by the niche due to its easy identification and welldefined surrounding cells. We have shown that the niche controls GSC self-renewal, anchorage, aging, and competition, and the GSC also signals back to the niche for its maintenance. The FSC is an attractive model for studying epithelial stem cell regulation and signal integration because we have shown that it resembles mammalian epithelial stem cells and requires multiple signaling pathways for its self-renewal. In this chapter, we have highlighted the findings of our studies on interactions between Drosophila ovarian stem cells and their niches during normal development and aging and on stem cell competition for niche occupancy. We further discuss their implications in general stem cell biology and future directions in this exciting area.

Secretory expression of insulin precursor in pichia pastoris and simple procedure for producing recombinant human insulin

In this work, Pichia pastoris was applied to produce human insulin by a simple procedure. The synthesized insulin precursor (ILP) gene was inserted into pPIC9K to obtain secretary expression plasmid pPIC9K/ILP. Pichia pastoris GS115 was transformed by pPIC9K/ILP and the high expresser was screened. In a 16 L fermentor, the insulin precursor production was 3.6 g/L. Insulin precursor, purified by one-step chromatography, was converted into human insulin by transpeptidation. The yield of the processing procedure from insulin precursor to insulin reached up to 70%. In vivo assay showed that the biological activity of the produced recombinant human insulin was 28.8 U/mg.

Effect of zoledronic acid (Zol) compared with placebo on overall disease and bone lesion progression in patients (pts) with bone metastases from certain solid tumors: Stratification by baseline characteristics

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Background: Zol has been shown to significantly reduce the risk of skeletal complications compared with placebo in pts with bone metastases from a wide range of solid tumors including a delay of bone lesion progression in pts with renal cancer. To assess whether Zol may reduce the risk of overall disease or bone lesion progression in pts with solid tumors other than breast, non-small cell lung, and prostate cancers, we conducted a retrospective analysis of pts enrolled in a large, randomized, controlled trial. Methods: Pts treated with Zol or placebo were retrospectively stratified by baseline characteristics, including Brief Pain Inventory (BPI) composite pain score, time from initial cancer diagnosis to development of bone metastases, and duration of cancer. The relative risk (RR) of disease progression during 25 months on study was analyzed using the Cox proportional hazards model (stratified log rank). Results: Median baseline BPI pain score was 2.75, median time with cancer was 15 months, and median time to development of bone metastases was 8.5 months. In pts with a baseline BPI score ≥ 2.75 (n = 236), Zol treatment significantly reduced the RR of disease progression by 34% (hazard ratio [HR] = 0.657; P = .014) and the RR of bone lesion progression by 32% (HR = 0.680; P = .028) compared with placebo. Additionally, in pts with cancer duration <15 months (n = 193), Zol treatment reduced the RR of disease progression by 45% (HR = 0.547; P = .002) and the RR of bone lesion progression by 40% (HR = 0.605; P = .016) compared with placebo. Similarly, among pts who developed bone metastases < 8.5 months from initial diagnosis of cancer (n = 193), Zol treatment significantly reduced the RR of disease progression by 39% and the RR of bone lesion progression by 48% compared with placebo (HR = 0.611; P = .009 and HR = 0.519; P = .004, respectively). Conclusions: This exploratory analysis suggests that Zol has potential antitumor effects that may reduce the risk of overall disease and bone lesion progression in pts who have higher pain scores and shorter time to development of bone metastases. Prospective studies are needed to confirm this result.

[Table: see text]

Effect of zoledronic acid (Zol) compared with pamidronate (Pam) on disease progression in breast cancer (BC) patients with bone metastases stratified by baseline characteristics

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Background: Zol has been shown to significantly reduce the risk of skeletal complications compared with Pam in BC pts with bone metastases. Zol has also demonstrated antitumor effects in animal models of human BC and significantly delayed bone lesion progression in pts with renal cancer. To assess whether Zol may reduce the risk of overall disease progression compared with Pam, we conducted a retrospective analysis of BC pts enrolled in a large randomized, controlled trial. Methods: Patients treated with Zol or Pam were retrospectively stratified by baseline characteristics, including Brief Pain Inventory (BPI) composite pain score, time from initial cancer diagnosis to development of bone metastases, and duration of cancer. The relative risk of overall disease progression during 25 months on study was analyzed using the Cox proportional hazards model. Results: Median BPI pain score at baseline was 2.75, median time to development of bone metastases was 44 months, and median time with cancer was 58 months for all patients. In the subset of pts with a baseline BPI score ≥ 2.75 (n = 556), treatment with Zol significantly reduced the risk of disease progression by 21% compared with Pam (hazard ratio [HR] = 0.793; P = .018). Similarly, among pts who developed bone metastases < 44 months from initial diagnosis of cancer (n = 564) and pts with cancer for < 58 months (n = 563), treatment with Zol reduced the risk of disease progression by approximately 20% compared with Pam (HR = 0.805; P = .026 and HR = 0.800; P = .023, respectively). Conclusions: Zol significantly reduced the risk of overall disease progression compared to Pam in specific subsets of pts with higher pain scores and shorter time to development of bone metastases. This exploratory analysis suggests that Zol has potential antitumor effects that may reduce the risk of disease progression in this patient population. These results are consistent with published reports and provide the initiative for further investigations with additional clinical studies.

[Table: see text]

Simultaneous determination of positional isomers of benzenediols by capillary zone electrophoresis with square wave amperometric detection

A capillary zone electrophoresis method coupling square wave amperometric detection (SWAD) for the simultaneous determination of positional isomers of benzendiols (i.e. o-, m-, p-benzenediols) has been developed. Effects of several factors, such as the composition of the running buffer, the pH value, separation voltage, injection time and the potential applied to the working electrode, were investigated to acquire the optimum conditions. The efficacy of the boric acid and ascorbic acid in the running buffer were discussed. o-, m-, p-Benzendiols can be well separated within 8 min in a 50 cm length of 50 microm diameter fused-silica capillary at a separation voltage of +15 kV. Operated in a wall-jet configuration, a 100 microm Pt-disk electrode used as the working electrode exhibits good response for the analytes. The relation between peak current and analyte concentration was linear over two orders of magnitude with detection limits (S/N = 3) ranging from 0.5 to 1.5 microM for all analytes. The proposed method has been successfully applied to monitor the o-, m-, p-benzendiols contents in the environmental wastewater samples with satisfactory assay results.

[Enantioseparation of tropicamide by capillary electrophoresis with square wave amperometric detection]

An enantioseparation method for tropicamide by high performance capillary electrophoresis with square wave amperometric detection (SWAD) was developed. The enantiomers of tropicamide were baseline separated in 16 min with an uncoated fused-silica capillary (75 microm i.d. x 50 cm) under the optimum conditions: 7 mmol/L Tris-10 mmol/L citric acid-2 mmol/L H3BO(3)-15 mmol/L beta-cyclodextrin (beta-CD) (pH 3.0) as background electrolyte, SWAD balance potential (E(b)) + 0.80 V (vs. Ag/AgCl), separation voltage 15 kV, injection height 20 cm, and injection time 10 s. The calibration curve of the enantiomers showed good linearity in the range from 5 micromol/L to 750 micromol/L with detection limit of 2 micromol/L. The average recoveries of added standards were 96% - 103%. The effects of the concentrations of beta-CD and the boric acid, the pH of the background electrolyte on resolutions (Rs) of the enantiomers were discussed in details. The proposed method was applied to the determination of a commercial tropicamide eye-drops sample without pre-treatment, and satisfactory results were obtained.

Experimental and theoretical study of the infrared spectra of BrHI− and BrDI−

Gas phase vibrational spectra of BrHI- and BrDI- have been measured from 6 to 17 microm (590-1666 cm(-1)) using tunable infrared radiation from the free electron laser for infrared experiments in order to characterize the strong hydrogen bond in these species. BrHI-.Ar and BrDI-.Ar complexes were produced and mass selected, and the depletion of their signal due to vibrational predissociation was monitored as a function of photon energy. Additionally, BrHI- and BrDI- were dissociated into HBr (DBr) and I- via resonant infrared multiphoton dissociation. The spectra show numerous transitions, which had not been observed by previous matrix studies. New ab initio calculations of the potential-energy surface and the dipole moment are presented and are used in variational ro-vibrational calculations to assign the spectral features. These calculations highlight the importance of basis set in the simulation of heavy atoms such as iodine. Further, they demonstrate extensive mode mixing between the bend and the H-atom stretch modes in BrHI- and BrDI- due to Fermi resonances. These interactions result in major deviations from simple harmonic estimates of the vibrational energies. As a result of this new analysis, previous matrix-isolation spectra assignments are reevaluated.

Human catechol-O-methyltransferase down-regulation by estradiol

Catechol-O-methyltransferase (COMT) is a crucial enzyme in dopamine and levodopa metabolism. Previously we reported that physiological concentrations of 17beta-estradiol (E2) down-regulated steady-state 1.3-kb COMT mRNA levels in MCF-7 cells. In this study, we investigated whether similar reductions occurred in a glial cell line (U138MG) and whether COMT protein and activity levels paralleled the reduction in COMT mRNA levels in MCF-7 cells. In addition, we explored the mechanism of E2 action. E2 had no effect on COMT mRNA levels in U138MG cells, but significantly reduced COMT protein and activity in MCF-7 cells (activity by 53% at 10(-7) M of E2, by 45% at 10(-8) M, and by 28% at 10(-9) M relative to non-E2-treated cells). A specific estrogen receptor antagonist (ICI 182780) blocked these estrogenic effects. Estrogen receptor in nuclear extracts of MCF-7 cells, which were pretreated with E2 (10(-9) M) for 48 h, bound to the whole proximal and distal promoter regions, as determined by electrophoretic mobility shift analysis (EMSA). We propose that E2 decreased COMT activity through down-regulation of its gene and protein expression mediated via ER interaction with response elements in the promoter region of the gene. Our findings may explain the lower of COMT activity in women compared to that in men, and, in part, the beneficial effects of E2 therapy in post-menopausal Parkinson's disease patients.

Detection of tumorigenesis in urinary bladder with optical coherence tomography: optical characterization of morphological changes

Most transitional cell tumorigenesis involves three stages of subcellular morphological changes: hyperplasia, dysplasia and neoplasia. Previous studies demonstrated that owing to its high spatial resolution and intermediate penetration depth, current OCT technology including endoscopic OCT could delineate the urothelium, submucosa and the upper muscular layers of the bladder wall. In this paper, we will discuss the sensitivity and limitations of OCT in diagnosing and staging bladder cancer. Based on histomorphometric evaluations of nuclear morphology, we modeled the resultant backscattering changes and the characteristic changes in OCT image contrast. In the theoretical modeling, we assumed that nuclei were the primary sources of scattering and were uniformly distributed in the uroepithelium, and compared with the results of the corresponding prior OCT measurements. According to our theoretical modeling, normal bladder shows a thin, uniform and low scattering urothelium, so does an inflammatory lesion except thickening in the submucosa. Compared with a normal bladder, a hyperplastic lesion exhibits a thickened, low scattering urothelium whereas a neoplastic lesion shows a thickened urothelium with increased backscattering. These results support our previous animal study that OCT has the potential to differentiate inflammation, hyperplasia, and neoplasia by quantifying the changes in urothelial thickening and backscattering. The results also suggest that OCT might not have the sensitivity to differentiate the subtle morphological changes between hyperplasia and dysplasia based on minor backscattering differences.

A murine dopamine neuron-specific cDNA library and microarray: increased COX1 expression during methamphetamine neurotoxicity

Due to brain tissue heterogeneity, the molecular genetic profile of any neurotransmitter-specific neuronal subtype is unknown. The purpose of this study was to purify a population of dopamine neurons, construct a cDNA library, and generate an initial gene expression profile and a microarray representative of dopamine neuron transcripts. Ventral mesencephalic dopamine neurons were purified by fluorescent-activated cell sorting from embryonic day 13.5 transgenic mice harboring a 4.5-kb rat tyrosine hydroxylase promoter-lacZ fusion. Nine-hundred sixty dopamine neuron cDNA clones were sequenced and arrayed for use in studies of gene expression changes during methamphetamine neurotoxicity. A neurotoxic dose of methamphetamine produced a greater than twofold up-regulation of the mitochondrial cytochrome c oxidase polypeptide I transcript from adult mouse substantia nigra at 12 h posttreatment. This is the first work to describe a gene expression profile for a neuronal subtype and to identify gene expression changes during methamphetamine neurotoxicity.

The structure dependent electrochemical-response of novel 1-(4-mercaptobutyl)-4-(2-ferrocenylvinyl)pyridinium bromide SAMs on an au electrode

The 1-(4-mercaptobutyl)-4-(2-ferrocenylvinyl)pyridinium bromide (1-HS(CH2)(4)-4-[(E)-FcCH=CH]C5H4N)+Br- and its hydrogenated product [1-HS(CH2)(4)-4-(-FcCH2CH2)C5H4N]+Br- were synthesized and assembled on an Au electrode to form self-assembled monolayers which showed a structure-dependent electrochemical-response in phosphate buffer aqueous solutions (pH = 7).

STAT5b is required for GH-induced liver IGF-I gene expression

Although the increased expression of Igf-I in liver in response to GH is well characterized, the intracellular signaling pathways that mediate this effect have not been identified. Intracellular signaling molecules belonging to the Janus kinase-signal transducer and activator of transcription 5b (JAK2-STAT5b) pathway are activated by GH and have previously been shown to be required for sexually dimorphic body growth and the expression of liver cytochrome P450 proteins known to be regulated by the gender-specific temporal patterns of pituitary GH secretion. Here, we evaluate the role of STAT5b in GH activation of Igf-I by monitoring the induction of Igf-I mRNA in livers of wild-type and Stat5b(-/-)mice stimulated with exogenous pulses of GH. GH induced the expression of liver Igf-I mRNA in hypophysectomized male wild-type, but not in hypophysectomized male Stat5b(-/-) mice, although the Stat5b(-/-) mice exhibit both normal liver GH receptor expression and strong GH induction of Cytokine-inducible SH2 protein (Cis), which is believed to contribute to the down-regulation of GH-induced liver STAT5b signaling. Thus, STAT5b plays an important and specific role in liver Igf-I gene expression.